Semiconductor laser

Abstract

A semiconductor laser includes a base, an epitaxial structure on the base, and a first electrode and a second electrode on the epitaxial structure. The epitaxial structure includes a first semiconductor structure on the base, a second semiconductor structure on the first semiconductor structure, an intermediate layer on the second semiconductor structure, a third semiconductor structure on the intermediate layer, a current-confining layer in the third semiconductor structure, a fourth semiconductor structure on the third semiconductor structure, and an active structure between the third semiconductor structure and the fourth semiconductor structure. The first electrode and the second electrode are on the fourth semiconductor structure, wherein a part of the first electrode passes through the fourth semiconductor structure, the active structure, the current-confining layer and the third semiconductor structure and is connected to the intermediate layer.

What is claimed is: 
     
         1 . A semiconductor laser, comprising:
 a base, having a first surface and a second surface, the first surface being a light exiting surface;   an epitaxial structure, located on the second surface of the base, and sequentially comprising:
 a first semiconductor structure; 
 a second semiconductor structure, located on the first semiconductor structure; 
 an intermediate layer, located on the second semiconductor structure; 
 a third semiconductor structure, located on the intermediate layer; 
 a current-confining layer, located in the third semiconductor structure; 
 a fourth semiconductor structure, located on the third semiconductor structure; and 
 an active structure, located between the third semiconductor structure and the fourth semiconductor structure; and 
   a first electrode and a second electrode, located on the fourth semiconductor structure, wherein a part of the first electrode penetrates the fourth semiconductor structure, the active structure and the third semiconductor structure and is connected to the intermediate layer.   
     
     
         2 . The semiconductor laser according to  claim 1 , further comprising:
 a optical component, located on the first surface of the base.   
     
     
         3 . The semiconductor laser according to  claim 1 , wherein the base is a gallium arsenide (GaAs) substrate. 
     
     
         4 . The semiconductor laser according to  claim 1 , wherein the intermediate layer comprises p-gallium arsenide (p-GaAs) or p-indium gallium phosphide (InGaP). 
     
     
         5 . The semiconductor laser according to  claim 4 , wherein the intermediate layer has a p-type or n-type conductivity type. 
     
     
         6 . The semiconductor laser according to  claim 1 , wherein a thickness of the intermediate layer is an odd-number multiple of ¼n of a light emitting wavelength of the semiconductor laser, wherein n is a refractive index. 
     
     
         7 . The semiconductor laser according to  claim 1 , further comprising a contact layer located on the fourth semiconductor structure. 
     
     
         8 . The semiconductor laser according to  claim 7 , further comprising a mirror layer located on the contact layer. 
     
     
         9 . The semiconductor laser according to  claim 8 , wherein the mirror layer is embedded in the second electrode. 
     
     
         10 . The semiconductor laser according to  claim 1 , wherein the base includes an undoped base layer. 
     
     
         11 . The semiconductor laser according to  claim 1 , wherein at least one of the first semiconductor structure, the second semiconductor structure, the third semiconductor structure and the fourth semiconductor structure includes a distributed Bragg reflector structure. 
     
     
         12 . The semiconductor laser according to  claim 11 , wherein each of the second semiconductor structure and the third semiconductor structure includes the distributed Bragg reflector structure, and a number of pairs of the distributed Bragg reflector in the second semiconductor structure is smaller than a number of pairs of the distributed Bragg reflector in the third semiconductor structure. 
     
     
         13 . The semiconductor laser according to  claim 1 , wherein a surface of the base includes patterned surface structures. 
     
     
         14 . The semiconductor laser according to  claim 13 , wherein the base is a glass substrate.